Structural, mechanical, electronic and optical properties of MFe2O4(M=Zn, Cu, Si) ferrites for electrochemical, photocatalytic and optoelectronic applications

First principles density functional calculations within the Cambridge Serial Total Energy Package (CASTEP) code applied to widely explore structural, mechanical, electronic and optical properties of MFe2O4 (M = Zn, Cu, Si) ferrites at pressures 0, 5, 10, 15, 20 GPa. The computed X-ray diffraction patterns showed that the lattice parameter values for MFe2O4 (M = Zn, Cu, Si) ferrites were 8.48-8.08 angstrom, 8.32-8.14 angstrom, and 8.23-7.87 angstrom, respectively at external pressure 0-20 GPa. The energy bandgap of the MFe2O4 (M = Zn, Si) ferrites revealed a direct nature within the range 1.24-0.0.82 eV and 3.843-3.484 eV versus 0-20 GPa external pressure, respectively. The CuFe2O4 ferrite exhibited indirect bandgaps ranging from 1.167 to 0.992 eV versus 0-20 GPa external pressure. Hence, all the computed values of the band gap showed an inverse response to applied pressure. Mulliken population and the total density of state confirmed that all the bonds Fe-O, Zn-O, Si-O, and Cu-O were covalent. The mechanical properties revealed the cubic stability of MFe2O4 (M = Zn, Cu, Si) ferrites. So, these ferrites proved potential candidates in electrochemical applications. The B/G values presented that the MFe2O4 (M = Zn, Cu) ferrites were ductile and considered suitable candidates in photocatalytic applications. In contrast, the SiFe2O4 ferrite exhibited brittle behavior at all the values of external pressure 0-20 GPa and was deemed helpful to optoelectronic devices. The optical properties showed that MFe2O4 (Zn, Cu, Si) ferrites showed excellent photosensitivity to visible light in photocatalytic, solar cells and optoelectronic applications.